A router (or router chassis) is a system that links computing devices to the Internet and may operate by choosing the best path for data to traverse the Internet to its destination. The router may typically include a number of modules or cards, such as for example line cards, fabric cards, and management cards. The line cards provide ingress and egress packet processing functionalities, the fabric cards are responsible for moving packets between the line cards, and the management cards execute the control plane software that is the user interface to the switch or router.
The various cards may include a number of application-specific integrated circuits (ASICs) designed for Ethernet switching and/or routing typically have Ethernet ports to interact with other Ethernet switches or routers. Each ASIC or groups of ASICs of the router may run its own Ethernet switching or routing stack. All the modules or cards are powered by a common power bus or busses within the router. For example, a router may support the use of multiple power supplies that collectivity provide a 12 volt bus that powers the modules within the router.